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Poster: tigerbolt Date: Jul 18, 2007 9:14pm
Forum: GratefulDead Subject: Re: 9/17/82

DTS Digital Surround is a 5.1-channel surround sound format, similar to Dolby Digital. As such it is a competing format to Dolby Digital. DTS (Digital Theater System) features up to five discrete (independent) channels (front center, front left, front right, surround left, surround right; giving it the "5" designation) of full frequency sound (with respect to the range of human hearing, which ideally ranges from 20 Hz to 20,000 Hz), plus a sixth channel for low frequency effects (LFE). The LFE signal is usually reserved for the subwoofer speaker(s), or those speakers capable of reproducing low frequency ranges. The low frequency effects channel gives DTS the ".1" designation. The ".1" signifies that the sixth channel is not full frequency, as it contains only deep bass frequencies (3 Hz to 120 Hz).

DTS is a lossy audio encoding scheme that supports up to 5.1 channels of discrete audio. Though the vast majority of DTS digital surround soundtracks consist of 5.1 channels, the fact is that it can be composed of less than 5.1 discrete channels. For example, DTS 4.0 have discrete audio signals for the center, left, and right channels, plus a mono audio signal that is common for the surround channels. DTS 4.1 is like DTS 4.0, but adds the ".1" low frequency effects channel. DTS 5.0 is like DTS 5.1, but lacks a discrete audio signal for the low frequency effects channel. Keep in mind that "DTS" does not always equate to "DTS 5.1". "DTS" generically refers to the encoding scheme as discussed above. Only when it says "DTS 5.1" explicitly can you be sure that the soundtrack consists of 5.1 discrete channels. Fortunately, the vast majority of DTS encoded DVDs are in fact DTS 5.1.

DTS uses higher data rates (1.5 Mbit/sec or 754 kbit/sec, which are almost twice to four times higher) to encode the 5.1 channels of surround sound information than Dolby Digital (448 kbit/sec or 384 kbit/sec), prompting many home theater enthusiasts and industry experts to claim that it is superior to Dolby Digital. DTS surround sound encoded DVD-Video titles are far fewer in number than their Dolby Digital counterparts, and until recently were released months after their Dolby Digital counterparts. Thanks to the new lower DTS data rate (i.e., the 754 kbit/sec data rate), some studios (e.g., Buena Vista, DreamWorks, Fox, New Line and to a lesser extent Columbia TriStar and Artisan) have begun to release DVD titles that feature both Dolby Digital 5.1 and DTS 5.1. Prior to the advent of the lower DTS data rate, DTS DVD titles featured the full DTS data rate (i.e., the 1.5 Mbit/sec data rate) soundtrack, a Dolby Surround 2.0 soundtrack (for backwards compatibility with non-DTS equipment), and few (if any) bonus material since capacity of the DVD was limited due to the "data hogging" full-rate DTS soundtrack.

To take advantage of DTS digital surround, you must have either configuration (A) or (B):

Configuration (A): DTS decoding in the receiver or preamplifier (this is the preferred configuration)
(1) a receiver or preamplifier with built-in DTS decoding (look for the "DTS" logo on the faceplate), and
(2) a DVD player with DTS digital output (look for the "DTS" or "DTS digital out" logo on the faceplate). Alternatively you can use a DVD player with DTS decoding built-in with its digital output (in which case you're not really using the decoder in the DVD player), and
(3) use an optical or coaxial digital audio interconnect to connect the DVD player to the receiver or preamplifier

Configuration (B): DTS decoding in the DVD player
(1) a "5.1-channel ready" receiver or preamplifier (with no DTS decoding) that has a set of 5.1-channel analog inputs, and
(2) a DVD player with built-in DTS decoding (look for the "DTS digital surround" logo on the faceplate and a set of 5.1-channel analog outputs on the back panel), and
(3) use six analog audio interconnects (i.e., three stereo RCA pairs) between the DVD player and the receiver or the regular version if you don't have the proper decoder.